Lichen Planus: exaggerated skin markings and scales; polygonal, purple, pruritic, flat topped
papules and plaques; Koebner’s phenomenon (i.e., the
appearance of lesions at sites of trauma) ; Flexor surfaces and
mucous membranes are commonly involved, but
the lesions can also be eruptive

Lichenoid Drug eruption: similar in appearance to those of
lichen planus but are usually seen in photo distributed areas; Labetelol etc can cause it; two entities can be distinguished histologically; lichen planus, there
is a bandlike lymphohistiocytic infiltrate at the
dermoepidermal junction, whereas in patients
with a lichenoid drug eruption, there are eosinophils and plasma cells in the infiltrate

Sarcoidiosis: may occur in many different morphologic forms,
including scaly papules or plaques ; The lesions
may be generalized (as they were in this patient),
but cutaneous sarcoidosis most commonly occurs
along the nares or lips or in scars ; Lymph node involvement is common

Psoriasis (BB like labetelol can cause it, usually is diffuse in such case): pink
scaly plaques that are usually well demarcated
and keratotic; Psoriasis is most commonly seen
on extensor surfaces or in areas of friction, but
it can be widespread in severe cases or when it is
induced by drugs,2 including beta-blockers such
as labetalol

Dyshidrotic Eczema: pruritic and can be accompanied by wide-
spread nummular eczema or atopic dermatitis

Infectious Disease

Secondary Syphilis

Eythema nodosum Leprosum: immune-complex reaction that occurs during
treatment of borderline and lepromatous leprosy,
can be manifested by eruptive erythematous
plaques and nodules, along with systemic symp-
toms, including painful lymphadenopathy.

Malignancy

Kaposi Sarcoma: purple
erythematous plaques and nodules; limited
to one arm or leg but can be widespread; usually accompanied by lymphedema; skin-biopsy specimen would reveal spindle cells with slitlike vascular spaces that
would be positive for human herpesvirus 8 on
immunohistochemical staining

Mast Cell Disease: Widespread pruritic papules and plaques can be
associated with cutaneous mastocytosis; Although urticaria pigmentosa lesions can easily urticate
(Darier’s sign) in children, this feature is less
common in adults ;Urticaria pigmentosa is more
likely to be associated with systemic disease and
hematologic cancer or mast-cell leukemia in
adults than it is in children; rarely scaly;

Primary Cutaneous T-cell lymphoma: can be
manifested by pruritic scaly plaques and papules
that usually occur on the buttocks and other
nonphotodistributed areas and appear gradually; There are several types of primary cutaneous T-cell
lymphoma, including

mycosis fungoides (which
is the most common): patch, plaque, or tumor and may also progress
to involve the lymph nodes and viscera